Caprolactam recovery device

Abstract

The utility model relates to a caprolactam recovery device. An outlet of a circulating tank is connected with an inlet of a membrane filtration system through a transfer pump; an outlet of the membrane filtration system is connected with an inlet of the ultrafiltration water production tank; an outlet of the ultrafiltration water production tank is connected with an inlet of the cation exchanger through the transfer pump; an outlet of the cation exchanger is connected with an inlet of the anion exchanger; the outlet of the anion exchanger is connected with the inlet of the desalted water tank. The treatment process of the recovery device is as follows: a caprolactam solution with the content of 8%-10% is filtered through a ceramic membrane, filtrate obtained after filtration passes through a cation resin tower and then passes through an anion resin tower, and effluent is conveyed to a reuse work section for reuse after the pH value of the effluent is finely adjusted. According to the method, the problem of recycling low-concentration caprolactam in the caprolactam wastewater is solved, and the loss of the caprolactam raw material in the production process is avoided.

Description

Technical Field

[0001] The utility model relates to a caprolactam recovery device and belongs to the field of wastewater resource utilization. Background Art

[0002] The caprolactam aqueous solution obtained after benzene extraction and water stripping in the caprolactam production process also contains trace amounts of impurities such as silicon, iron, aluminum, manganese, potassium, and calcium. These impurities will continue to remain in the polymer, eventually causing floating fibers and broken ends during the spinning process, ultimately leading to a decline in product quality and requiring desalination treatment. The traditional treatment method treats this part of the caprolactam wastewater as organic wastewater, resulting in the loss of caprolactam. The utility model can achieve the recycling of caprolactam. Summary of the invention

[0003] The utility model aims to provide a device to solve the problem of recovering caprolactam in caprolactam waste water.

[0004] A caprolactam recovery device, wherein the outlet of the circulation tank is connected to the inlet of the membrane filtration system via a transfer pump;

[0005] The outlet of the membrane filtration system is connected to the inlet of the ultrafiltration water production tank;

[0006] The outlet of the ultrafiltration water production tank is connected to the inlet of the cation exchanger via a transfer pump;

[0007] The cation exchanger outlet is connected to the anion exchanger inlet;

[0008] The anion exchanger outlet is connected to the desalted water tank inlet.

[0009] A cation regeneration liquid inlet pipe is arranged at the lower part of the cation exchanger; and pure water inlet pipes are arranged at the lower part and the upper part of the cation exchanger respectively.

[0010] The lower part of the anion exchanger is provided with an anion regeneration liquid inlet pipe; the lower part and the upper part of the anion exchanger are respectively provided with pure water inlet pipes.

[0011] The membrane filtration systems are two or more, and adjacent membrane filtration systems are connected in parallel.

[0012] There are two or more cation exchangers, and adjacent cation exchangers are connected in parallel.

[0013] There are two or more anion exchangers, and adjacent anion exchangers are connected in parallel.

[0014] The outlet of the anion exchanger is connected to a buffer tank, a baffle is arranged in the buffer tank, and an acid liquid inlet pipe is arranged on the buffer tank.

[0015] The caprolactam recovery device described in the utility model has the following processing flow: the caprolactam wastewater with a content of 8% to 10% is first filtered through a ceramic membrane, the filtered filtrate first passes through a cationic resin tower, and then passes through an anionic resin tower, and the effluent is transported to the reuse section for reuse after the pH value is fine-tuned.

[0016] The 8% to 10% caprolactam wastewater has a temperature of 94° C. and contains trace amounts of impurities such as silicon, iron, aluminum, manganese, potassium, and calcium.

[0017] The ceramic membrane has a filtration accuracy of 20 nm, adopts cross-flow circulation filtration, and the water recovery rate is not less than 95%. The single membrane flux is 300 L / (m 2 h).

[0018] The cationic resin tower has a flow rate of 20-30 m / h, and 3-4% hydrochloric acid countercurrent regeneration is used during regeneration, with a regeneration flow rate of 4-6 m / h and a regeneration cycle of 168 h. The cationic resin tower is filled with high temperature resistant (90°C-100°C) cationic resin, with an effective particle size of 0.5 mm-0.7 mm and an adsorption capacity of 1800 mol / m 3 .

[0019] The anion resin tower has a flow rate of 20-30 m / h, and adopts 3-4% liquid alkali countercurrent regeneration during regeneration, with a regeneration flow rate of 4-6 m / h and a regeneration cycle of 168 h. The anion resin tower is filled with high temperature resistant (90°C-100°C) anion resin, with an effective particle size of 0.5 mm-0.7 mm and an adsorption capacity of 1300 mol / m 3 .

[0020] The resin in the cationic resin tower is SQ-681GH; the resin in the anionic resin tower is SQ-742GH.

[0021] The utility model has the following advantages:

[0022] (1) The device of the utility model can fully recover caprolactam in wastewater without losing caprolactam;

[0023] (2) The recovered caprolactam contains no other impurities and has high recycling value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural diagram of the recovery device for caprolactam, wherein: circulation tank 1, membrane filtration system 2, material transfer pump 3, ultrafiltration water production tank 4, cation exchanger 5, anion exchanger 6, desalted water tank 7, buffer tank 8, cation regeneration liquid enters pipe A, anion regeneration liquid enters pipe B, and pure water enters pipe C. DETAILED DESCRIPTION

[0025] A caprolactam recovery device, wherein the outlet of a circulation tank 1 is connected to the inlet of a membrane filtration system 2 via a transfer pump 3;

[0026] The outlet of the membrane filtration system 2 is connected to the inlet of the ultrafiltration water production tank 4;

[0027] The outlet of the ultrafiltration water production tank 4 is connected to the inlet of the cation exchanger 5 via a transfer pump;

[0028] The outlet of the cation exchanger 5 is connected to the inlet of the anion exchanger 6;

[0029] The outlet of the anion exchanger 6 is connected to the inlet of the desalted water tank 7 .

[0030] A cation regeneration liquid inlet pipe A is provided at the lower part of the cation exchanger 5 ; pure water inlet pipes C are provided at the lower part and the upper part of the cation exchanger 5 , respectively.

[0031] The lower part of the anion exchanger 6 is provided with an anion regeneration liquid inlet pipe B; the lower part and the upper part of the anion exchanger 6 are respectively provided with pure water inlet pipes C.

[0032] The membrane filtration system 2 is two membrane filtration systems 2 connected in parallel.

[0033] The cation exchangers 5 are two cation exchangers 5 connected in parallel.

[0034] The anion exchangers 6 are two anion exchangers 6 connected in parallel.

[0035] The outlet of the anion exchanger 6 is connected to a buffer tank 8 , a baffle is arranged inside the buffer tank 8 , and an acid liquid inlet pipe is arranged on the buffer tank 8 .

[0036] Example 2

[0037] The device of Example 1 is used to carry out the following process:

[0038] The caprolactam content in the caprolactam wastewater of a chemical group is 8%. This method is used for treatment. The specific treatment steps are as follows:

[0039] (1) The wastewater is first filtered through a ceramic membrane;

[0040] (2) After the previous step is completed, the water produced by the ceramic membrane is transported to the cationic resin tower, and the flow rate of the resin tower is 20m / h;

[0041] (3) After the previous step is completed, the water produced by the cation resin tower is transported to the anion resin tower, and the flow rate of the resin tower is 20m / h;

[0042] (4) After the previous step is completed, the water produced by the anion resin tower is sent to the reuse section for reuse after the pH value is adjusted.

[0043] Example 3

[0044] The device of Example 1 is used to carry out the following process:

[0045] The caprolactam content in the caprolactam wastewater of a chemical group is 10%. This method is used for treatment. The specific treatment steps are as follows:

[0046] (1) The wastewater is first filtered through a ceramic membrane;

[0047] (2) After the previous step is completed, the water produced by the ceramic membrane is transported to the cationic resin tower, and the flow rate of the resin tower is 30m / h;

[0048] (3) After the previous step is completed, the water produced by the cation resin tower is transported to the anion resin tower, and the flow rate of the resin tower is 30m / h;

[0049] (4) After the previous step is completed, the water produced by the anion resin tower is sent to the reuse section for reuse after the pH value is adjusted.

Claims

1. A caprolactam recovery device, characterized in that: The outlet of the circulation tank (1) is connected to the inlet of the membrane filtration system (2) via a transfer pump (3); The outlet of the membrane filtration system (2) is connected to the inlet of the ultrafiltration water production tank (4); The outlet of the ultrafiltration water production tank (4) is connected to the inlet of the cation exchanger (5) via a transfer pump; The outlet of the cation exchanger (5) is connected to the inlet of the anion exchanger (6); The outlet of the anion exchanger (6) is connected to the inlet of the desalted water tank (7).

2. The caprolactam recovery device according to claim 1, characterized in that: A cation regeneration liquid inlet pipe (A) is arranged at the lower part of the cation exchanger (5); and pure water inlet pipes (C) are arranged at the lower part and the upper part of the cation exchanger (5), respectively.

3. The caprolactam recovery device according to claim 1, characterized in that: An anion regeneration liquid inlet pipe (B) is arranged at the lower part of the anion exchanger (6); and pure water inlet pipes (C) are arranged at the lower part and the upper part of the anion exchanger (6), respectively.

4. The caprolactam recovery device according to claim 1, characterized in that: The membrane filtration systems (2) are two or more, and adjacent membrane filtration systems (2) are connected in parallel.

5. The caprolactam recovery device according to claim 1, characterized in that: There are two or more cation exchangers (5), and adjacent cation exchangers (5) are connected in parallel.

6. The caprolactam recovery device according to claim 1, characterized in that: There are two or more anion exchangers (6), and adjacent anion exchangers (6) are connected in parallel.

7. The caprolactam recovery device according to claim 1, characterized in that: The outlet of the anion exchanger (6) is connected to a buffer tank (8), a baffle is provided inside the buffer tank (8), and an acid liquid inlet pipe is provided on the buffer tank (8).

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